Carl Hjalmar August Johansson (20 January 1874 – 30 September 1957) was a Swedish pioneer diver, swimmer and track and field athlete who competed at the 1906, 1908 and 1912 Summer Olympics.
In 1906 he finished sixth in the combined platform diving event, eighth in the 100 m freestyle swimming and 19th in standing long jump event.
Two years later he won a gold medal in the 10 m diving platform and was eliminated in the heats of 200 m breaststroke.
In 1912, aged 38, he won a silver medal in the plain high diving event and finished fourth in the 10 m platform.
Johansson significantly contributed to designing the Olympic code for conduct of diving competitions. He also invented diving styles, such as the "Swedish Swallow". He won the Swedish diving title from 1897 to 1912, except for two years when he was studying in London, and the British title from 1907 to 1913. In 1982 he was inducted into the International Swimming Hall of Fame as an honor diver/contributor.